Need Help With AC Dryer Wiring

[GCecchetto]

On my way home today, when it was actually pretty warm, my AC wasn't working. Did some snooping around and found this when I got home: I noticed when the cab was up yesterday to install my trucklite turn signals that the cab was pinching and pulling on the wires to the dryer. I rerouted them so that is no longer an issue, but didn't notice this. Seems my life is redoing the work of the guy before me. Anyway, with two wires pulled out, I have no idea which goes where. Wires on the opposite side of the plug don't match, so that doesn't help me. Wires at the dryer side has the two blacks and two blues in a diagonal pattern, but that doesn't mean they should be that way at the plug. I realize I have a 50/50 chance of getting it right, but I don't want to damage anything since I don't know what's what with this wiring. Hoping someone has the same setup and get tell me where the loose wire go. Thanks

 

[GeneralDisorder]

Fortunately you can't screw anything up easily. The black wires on the trinary switch are the high/low pressure cut out switch for the compressor, and the blue wires are the AC condenser fan switch wires. That's standard convention for trinary switch wire colors in the AC world.

The truck side is likely the same. You can take a jumper wire and connect the two black pins on the harness side and with the truck running that should engage and disengage the compressor clutch. Likewise with the blue wires if you jump those it will run the AC condenser fans.

You have two remaining wires connected. Is the blue connected to one of the blue wires from the trinary switch? And is the black similarly connected to one of the black trinary switch leads? The choice of colors is usually not a coincidence.

And yeah - you'll find that pretty often you will be redoing someone else's job. Seems kinda absurd for a truck that cost $175k in 2008 doesn't it?

 

[GCecchetto]

Hey GD. Thanks for replying, don't know what I would do without you The wiring in the photo is at the plug on the dryer, the truck side of the harness is three black wires and a yellow. if the wiring was the same colors on both sides of the plug this would be easy. The whole plug basically fell apart. Since two wire had come out, thought it wise to check the other two. Gentle tug and they came right out. If there is no combination of jumping the pins that can damage anything, I can play with jumping the pins to figure it out. If I understand what you've explained, it's just black to black and blue to blue with no polarity to worry about correct? So I just need to figure out what's what on the truck side since that's three blacks and a yellow. I've yet to figure out how to get the pins out of the plug though. I have one of the kits with all the tools for this, but none seem correct. It seems the whole inner piece of the plugs comes out.

 

[GeneralDisorder]

So I'm about 99% sure that plug you are holding is the same one that was on my harness and is designed to connect directly to the trinary switch that Tom includes with his kits:

LMTV A/C parts

LMTV truck parts

www.lmtvtrucks.com

That switch is a weird unit and I didn't use it either - I elected to use a switch just like what you have and I provided the details of the pinout to the Hyundai switch that uses that connector. It looks like they found the matching harness connector for that switch..... I just lopped it off and put Deutsch DT 4-pin on in it's place for serviceability and to match a lot more of the stock stuff on the truck. I also extended the wires from that connecter with the 3 black and 1 yellow wire and changed them to the correct 2 blue and 2 black in the process and now my harness is all wrapped up and the only wire showing is at my trinary switch and connector and it's the same color on both sides PRECISELY to avoid the exact problem you are having.

All that is to say I am 99% sure your pinout is in my post that gives the pinout to the matching trinary switch:

Gen 2 air conditioning install with C7 A1R - notes and pictures thus far.

I'm told by a MotorPool veteran of 20 years that "soft cab" trucks were basically never equipped with AC. He couldn't recall ever seeing one in fact. The A1P2 armored cab trucks all have it and in fact AC malfunction is a deadline. The AC only has to drop the ambient temp by 20 degrees F to be...

www.steelsoldiers.com

 

[GCecchetto]

So I'm about 99% sure that plug you are holding is the same one that was on my harness and is designed to connect directly to the trinary switch that Tom includes with his kits:

LMTV A/C parts

LMTV truck parts

www.lmtvtrucks.com

That switch is a weird unit and I didn't use it either - I elected to use a switch just like what you have and I provided the details of the pinout to the Hyundai switch that uses that connector. It looks like they found the matching harness connector for that switch..... I just lopped it off and put Deutsch DT 4-pin on in it's place for serviceability and to match a lot more of the stock stuff on the truck.

All that is to say I am 99% sure your pinout is in my post that gives the pinout to the matching trinary switch:

Gen 2 air conditioning install with C7 A1R - notes and pictures thus far.

I'm told by a MotorPool veteran of 20 years that "soft cab" trucks were basically never equipped with AC. He couldn't recall ever seeing one in fact. The A1P2 armored cab trucks all have it and in fact AC malfunction is a deadline. The AC only has to drop the ambient temp by 20 degrees F to be...

www.steelsoldiers.com

I figured out the the pinout already this morning. I have Deutsch DT 4-pin connectors, so If i can't figure out how to get the pins out of this plug, I'll just change it out. Need to get this done so I can get on to figuring out where my power steering fluid is leaking from.